git@vger.kernel.org mailing list mirror (one of many)
 help / Atom feed
From: Оля Тележная  <olyatelezhnaya@gmail.com>
To: Martin Ågren <martin.agren@gmail.com>
Cc: Git Mailing List <git@vger.kernel.org>
Subject: Re: [RFC 3/4] ref-filter: change parsing function error handling
Date: Wed, 14 Mar 2018 16:36:33 +0300
Message-ID: <CAL21BmkPrgUtiuV=AMqnOwPX-aXdWU39CFLwGCAmMLvXBdLXWA@mail.gmail.com> (raw)
In-Reply-To: <CAN0heSrogCMT-8R4nht=_9syMNUfJe21BvZSVD4AUcf9PwN7rQ@mail.gmail.com>

2018-03-13 22:18 GMT+03:00 Martin Ågren <martin.agren@gmail.com>:
> On 13 March 2018 at 11:16, Olga Telezhnaya <olyatelezhnaya@gmail.com> wrote:
>> Continue removing any printing from ref-filter formatting logic,
>> so that it could be more general.
>>
>> Change the signature of parse_ref_filter_atom() by changing return value,
>> adding previous return value to function parameter and also adding
>> strbuf parameter for error message.
>
> I think the current return value is always non-negative. Maybe it would
> be easier to leave the return value as-is, except return negative on
> error? Unless I am missing something?

That's interesting. I like your idea, but let's see what other people think.
If others agree with us, I am ready to implement your solution.

>
>>
>> Signed-off-by: Olga Telezhnaia <olyatelezhnaya@gmail.com>
>> ---
>>  ref-filter.c | 45 ++++++++++++++++++++++++++++++++-------------
>>  1 file changed, 32 insertions(+), 13 deletions(-)
>>
>> diff --git a/ref-filter.c b/ref-filter.c
>> index 07bedc636398c..e146215bf1e64 100644
>> --- a/ref-filter.c
>> +++ b/ref-filter.c
>> @@ -397,7 +397,8 @@ struct atom_value {
>>   * Used to parse format string and sort specifiers
>>   */
>>  static int parse_ref_filter_atom(const struct ref_format *format,
>> -                                const char *atom, const char *ep)
>> +                                const char *atom, const char *ep, int *res,
>> +                                struct strbuf *err)
>>  {
>>         const char *sp;
>>         const char *arg;
>> @@ -406,14 +407,18 @@ static int parse_ref_filter_atom(const struct ref_format *format,
>>         sp = atom;
>>         if (*sp == '*' && sp < ep)
>>                 sp++; /* deref */
>> -       if (ep <= sp)
>> -               die(_("malformed field name: %.*s"), (int)(ep-atom), atom);
>> +       if (ep <= sp) {
>> +               strbuf_addf(err, _("malformed field name: %.*s"), (int)(ep-atom), atom);
>> +               return -1;
>> +       }
>>
>>         /* Do we have the atom already used elsewhere? */
>>         for (i = 0; i < used_atom_cnt; i++) {
>>                 int len = strlen(used_atom[i].name);
>> -               if (len == ep - atom && !memcmp(used_atom[i].name, atom, len))
>> -                       return i;
>> +               if (len == ep - atom && !memcmp(used_atom[i].name, atom, len)) {
>> +                       *res = i;
>> +                       return 0;
>> +               }
>>         }
>
> If you did so, this hunk above would not need to be changed ...
>
>> @@ -458,7 +465,8 @@ static int parse_ref_filter_atom(const struct ref_format *format,
>>                 need_tagged = 1;
>>         if (!strcmp(valid_atom[i].name, "symref"))
>>                 need_symref = 1;
>> -       return at;
>> +       *res = at;
>> +       return 0;
>>  }
>
> ... nor this one above ...
>
>>                 if (!ep)
>>                         return error(_("malformed format string %s"), sp);
>>                 /* sp points at "%(" and ep points at the closing ")" */
>> -               at = parse_ref_filter_atom(format, sp + 2, ep);
>> +               if (parse_ref_filter_atom(format, sp + 2, ep, &at, &err))
>> +                       die("%s", err.buf);
>
> And this would be more like "if (at < 0) die(...)".
>
>>         for (cp = format->format; *cp && (sp = find_next(cp)); cp = ep + 1) {
>>                 struct atom_value *atomv;
>> +               struct strbuf err = STRBUF_INIT;
>> +               int pos;
>>
>>                 ep = strchr(sp, ')');
>>                 if (cp < sp)
>>                         append_literal(cp, sp, &state);
>> -               get_ref_atom_value(info,
>> -                                  parse_ref_filter_atom(format, sp + 2, ep),
>> -                                  &atomv);
>> +               if (parse_ref_filter_atom(format, sp + 2, ep, &pos, &err))
>> +                       return -1;
>> +               get_ref_atom_value(info, pos, &atomv);
>>                 if (atomv->handler(atomv, &state, error_buf))
>>                         return -1;
>> +               strbuf_release(&err);
>
> This looks leaky: if we get an error, we've got something in the buffer
> but we do not release it because we return early. Stepping back a bit, I
> wonder why we do not do anything at all with "err". Stepping back a bit
> more :-) I wonder if you could get rid of "err" and pass "error_buf" to
> parse_ref_filter_atom() instead. Our caller would like to have access to
> the error string?

Fully agree, I don't know why I decided to create one more buffer. Fixed.

>
> This ties back to my comment on the first patch -- "return negative if
> and only if you add some error string to the buffer" might be a useful
> rule?
>
> Martin

  reply index

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-13 10:16 [RFC 1/4] ref-filter: start adding strbufs with errors Olga Telezhnaya
2018-03-13 10:16 ` [RFC 4/4] ref-filter: add return value to parsers Olga Telezhnaya
2018-03-13 10:16 ` [RFC 2/4] ref-filter: add return value && strbuf to handlers Olga Telezhnaya
2018-03-13 19:13   ` Martin Ågren
2018-03-13 10:16 ` [RFC 3/4] ref-filter: change parsing function error handling Olga Telezhnaya
2018-03-13 19:18   ` Martin Ågren
2018-03-14 13:36     ` Оля Тележная [this message]
2018-03-13 19:12 ` [RFC 1/4] ref-filter: start adding strbufs with errors Martin Ågren
2018-03-14 13:30   ` Оля Тележная
2018-03-14 19:04 ` [PATCH v2 1/5] " Olga Telezhnaya
2018-03-14 19:04   ` [PATCH v2 2/5] ref-filter: add return value && strbuf to handlers Olga Telezhnaya
2018-03-14 19:04   ` [PATCH v2 3/5] ref-filter: change parsing function error handling Olga Telezhnaya
2018-03-15 22:48     ` Junio C Hamano
2018-03-16  7:22       ` Оля Тележная
2018-03-14 19:04   ` [PATCH v2 4/5] ref-filter: add return value to parsers Olga Telezhnaya
2018-03-14 19:04   ` [PATCH v2 5/5] ref-filter: get_ref_atom_value() error handling Olga Telezhnaya
2018-03-15 20:47     ` Martin Ågren
2018-03-15 21:01       ` Eric Sunshine
2018-03-16  7:20         ` Оля Тележная
2018-03-15 21:05       ` Junio C Hamano
2018-03-16  7:17       ` Оля Тележная
2018-03-19 13:01   ` [PATCH v3 1/5] ref-filter: start adding strbufs with errors Olga Telezhnaya
2018-03-19 13:01     ` [PATCH v3 5/5] ref-filter: get_ref_atom_value() error handling Olga Telezhnaya
2018-03-19 13:01     ` [PATCH v3 4/5] ref-filter: add return value to parsers Olga Telezhnaya
2018-03-19 13:01     ` [PATCH v3 2/5] ref-filter: add return value && strbuf to handlers Olga Telezhnaya
2018-03-19 19:24       ` Junio C Hamano
2018-03-19 13:01     ` [PATCH v3 3/5] ref-filter: change parsing function error handling Olga Telezhnaya
2018-03-19 19:41       ` Junio C Hamano
2018-03-20 16:05     ` [PATCH v4 1/5] ref-filter: start adding strbufs with errors Olga Telezhnaya
2018-03-20 16:05       ` [PATCH v4 3/5] ref-filter: change parsing function error handling Olga Telezhnaya
2018-03-20 16:05       ` [PATCH v4 2/5] ref-filter: add return value && strbuf to handlers Olga Telezhnaya
2018-03-20 18:18         ` Eric Sunshine
2018-03-20 16:05       ` [PATCH v4 4/5] ref-filter: add return value to parsers Olga Telezhnaya
2018-03-20 16:05       ` [PATCH v4 5/5] ref-filter: get_ref_atom_value() error handling Olga Telezhnaya
2018-03-20 18:19         ` Eric Sunshine
2018-03-20 22:30           ` Junio C Hamano
2018-03-20 22:50             ` Eric Sunshine
2018-03-21 19:30               ` Junio C Hamano
2018-03-21 19:58                 ` Eric Sunshine
2018-03-21 18:28       ` [PATCH v5 1/6] strbuf: add shortcut to work with error messages Olga Telezhnaya
2018-03-21 18:28         ` [PATCH v5 3/6] ref-filter: add return value && strbuf to handlers Olga Telezhnaya
2018-03-21 18:28         ` [PATCH v5 6/6] ref-filter: libify get_ref_atom_value() Olga Telezhnaya
2018-03-21 18:28         ` [PATCH v5 4/6] ref-filter: change parsing function error handling Olga Telezhnaya
2018-03-21 20:36           ` Junio C Hamano
2018-03-23  6:56             ` Оля Тележная
2018-03-21 18:28         ` [PATCH v5 2/6] ref-filter: start adding strbufs with errors Olga Telezhnaya
2018-03-21 18:28         ` [PATCH v5 5/6] ref-filter: add return value to parsers Olga Telezhnaya
2018-03-21 20:20         ` [PATCH v5 1/6] strbuf: add shortcut to work with error messages Junio C Hamano
2018-03-23  6:48           ` Оля Тележная
2018-03-29 12:49         ` [PATCH v6 1/6] ref-filter: add shortcut to work with strbufs Olga Telezhnaya
2018-03-29 12:49           ` [PATCH v6 6/6] ref-filter: libify get_ref_atom_value() Olga Telezhnaya
2018-03-29 12:49           ` [PATCH v6 5/6] ref-filter: add return value to parsers Olga Telezhnaya
2018-03-29 12:49           ` [PATCH v6 3/6] ref-filter: add return value && strbuf to handlers Olga Telezhnaya
2018-03-29 12:49           ` [PATCH v6 4/6] ref-filter: change parsing function error handling Olga Telezhnaya
2018-03-29 12:49           ` [PATCH v6 2/6] ref-filter: start adding strbufs with errors Olga Telezhnaya

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

  List information: http://vger.kernel.org/majordomo-info.html

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='CAL21BmkPrgUtiuV=AMqnOwPX-aXdWU39CFLwGCAmMLvXBdLXWA@mail.gmail.com' \
    --to=olyatelezhnaya@gmail.com \
    --cc=git@vger.kernel.org \
    --cc=martin.agren@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

git@vger.kernel.org mailing list mirror (one of many)

Archives are clonable:
	git clone --mirror https://public-inbox.org/git
	git clone --mirror http://ou63pmih66umazou.onion/git
	git clone --mirror http://czquwvybam4bgbro.onion/git
	git clone --mirror http://hjrcffqmbrq6wope.onion/git

Newsgroups are available over NNTP:
	nntp://news.public-inbox.org/inbox.comp.version-control.git
	nntp://ou63pmih66umazou.onion/inbox.comp.version-control.git
	nntp://czquwvybam4bgbro.onion/inbox.comp.version-control.git
	nntp://hjrcffqmbrq6wope.onion/inbox.comp.version-control.git
	nntp://news.gmane.org/gmane.comp.version-control.git

 note: .onion URLs require Tor: https://www.torproject.org/
       or Tor2web: https://www.tor2web.org/

AGPL code for this site: git clone https://public-inbox.org/ public-inbox